Feed mechanism for grinding machines



Jan. 13,1931. c. E. VAN NORMAN FEED MECHANISM FOR GRINDING MACHINES Original Filed April 29, 1926 INVENTOR. M 5' W W;

ATTORNEY Patented Jan.;13, 1 931 *"uNireosTATEs PArEN; ,F cE;

CHARLES E. van NORMAN, or srniivegrinnn, MASSACI-IU SET'IS;JiSSIGNOR To VAN NORMAN MACHINE T0011 COMPANY, OF

RATION OF MASSACHUSETTS simmerinrn, MAssAc iUsE'TTs, A ccRPo- FEED MECHANISM FOR GRINDING MACHINES Original application filed'April 29, 1926, Serial No. 105,458.- Divided andthis application filed April 17,

- g 1928. Scria1 N'.-270,696. I a

This invention relates to precision grinding machines or thelike, and has particularthe grinding head in order to cause the'work to be graduallyreduced in size to the degree desired. One object of the invention is to provide a quick acting means for stopping the feeding action without afiecting the setting of the machine, so that feeding may be resumed immediately-when necessary; Another object is to provide mechanism by. which a relatively rapid feed for rough cutting may be maintained 'as'long as possible,

and a decrease in the speed forv the finishing cutmade without loss of time. Another object is to provide means for adjusting the feed mechanism to accommodate the progressive wear of the grinding wheel without changing the relative action of the feed decrease and the automatic stop mechanism. Further objects will appear from the following specification and claims.

Referring to the drawings:

Fig. 1 is a side elevation of the tool head of a grinding machine embodying my invention' r Fi g. 2is a View 011a larger scalev of:certain mechanism shown in Fig. 1, looking from the left in that figure;

Fig. 3 and F ig.-l 'arelsimilar viewsshow-,

ing the parts in tion;

Fig. 5

dilferent positions of operaof certain parts. j i

The machineis shown as a whole; in my prior applicationserial No. 105,458 filed April 29, 1926, of which the present case is a division. The "work holding head is not shownin thepresent case as notnecessary for is a side elevation of the mechanism shown in Fig. 2; and i Q Fig. 6 is a detail, illustrating theop'eratlon Referring now to the example shown, the machine. 1s carrledon abase 10, mounted in which is a slide 11 and a tool carrying slide 12. lhe slide 11 carries a rack 13' engaged by a pinion 1e operable through a handle 15 to givea quick movement to the slide, useful in backing the tool away from the work-head when a fresh work piece is tobe-inserted. l/Vhen the feed mechanism to be described is operating. a stop .16 on the slide 11 is in contact with an abutment 17 on the base.

1 Fastened to slide ll is a nut l8 engaging a screw 19 which isrotatable but axially hired in the slide 12. The screw 19 passes through aibearing-member'20 and carries a ratchet wheel 21. Upon ahub 22 of this ratchet is positioned a member 23, carrying certain partsto be described and held frictionallyin place by a clampiscrew 24. The frictional engagement is sufficient to holdtheniember and the ratchet together during the normal operation'of'the machine, but permitsthem to have a relative adjusting ,movement to provide a take-up as the grinding element gradually wears away.

- Upon. a bracket 25 carried by the bearing member 20 is a pawl carrier-26 pivoted upon a stud 27 Pivoted at 28 to this pawl carrier is a pawl 29 having a detent 3Q engaging the teeth of the ratchet 21, the pawlbeing pressed towards theratchetbya spring 81. A strike plate 32 movable-withthe pawl carrierhas a pin 33 to which is. attacheda spring 34: having b 7 its other end fastened to a pin 35 'on' the bracket 25. A rod 36 slides through the bracket 25 in'position to strike the plate 32 and bears at itslower end an adjustable tappct 37. 'Arocking; plate 38 is-pivoted to the base 10 at 39 andris oscillated by-a vertically reciprocating rod 40, which may be actuated t by anydesiredrneans, as for example, that shown inmy reissued March 16, 1 915.

patent 13,892 dated 7 The motion of the "rod 40, and hence of the rocking plate 38, is constant but-the-effect of it upon the rod36 varies with the I initial-distanceof rod 36 above the plate.

.This distanceis in the present instance subj ect to three separate controls'zthe adjustable tappet. 37 ,an automatic cam-operated control operable to reduce the feed at a predetermined time in the operationof the machine, and a hand-operated throw-oil by means of which the feed may be discontinued temporarily at anydesired instant. The tappet. 37 acts as a Vernier adjustment of the feed, and is set to the proper'spacing above the rocker 38 so t'hatthe rough feed given to the tool head during the" i'ntial portion of the grinding operation will be of the desired magnitude. y r

The cam control is secured by the following mechanism Pivoted to an extension 41:

, or the bearing as at 4L2 is avrockerflii car'- raised by the cam the screw acts as an abutment limiting the downward movement of the rod '36 and, therefore, deereasing'the upward movement which-the rod-is given bythe rocker 38. 5 1

If it is desiredto-r fierrapt the feedin'g of the work head'tempora rily at anytime the detent is removed from engagement with the ratchet teeth'by-t-he following mechanism: Slid'able in the bracket-25 is a' rod movable towards and away from the pawl 29, the upper end 51 of which is adaptedto strike the lower's'ide of the pawlflThe end of" the rod is preferably beveled as shown, so as to lie closer to the pawl and-present a striking surface substantially parallel tothat' of r'ered by tlie'paWlL' pin 52 on this red eX- tends through a slot in thebracket ancl'err gages the forked end 53 of a lever54r pivoted upon the bracket at55. To hold the lever in either extreme position; a pin 56 thereon bears against: a stationary-spring or friction plate 57, I j

Besides movingthe pawl out of contact with the" ratchet the lever 54 preferably also raises the rod 36 so that-it is either o'ut 'of contact-with the rocker 38 or has its motion somuch reduced that it eannotgmove the pawl into cont-act with the ratchet-and also removes cam roll 44 fromfconta'ct with the cam 45. This. is accomplishedthrough a bracket'58 secured by aset screw59'to the lower end of the rod 50 and bearing an adjustablestop screw 60 which, whenthe rod is raised. strikes the rocker l3 and tilts it i'n-the gaeed by the cam 45.

same directionas when i'ts cam; T011414 is en- It will-be observed that if the handle part of the lever 54 is pressed smartly downwardthe pawl 29 will be struclpa quick hammer blow by the rod end This action ef fectively disengages the detent 30 from the ratchet teeth, and, as the handle stays in its extreme position until moved back by the operator, holds the pawl out ofcontacteven though the rod 40 is continually moved up and down by its" actuating mechanism.

To stop the feed of the :work head a predetermined timeafter the start of the slow or fi'nisl'iiri'g feed,a pla'tee'l is carried upon the member 23. I This plate passes between the detent 30 and the ratchet wheel to stop further feeding motion. Also secured to the ,member is an extension 62 ;having pivoted t-heretozamember 63 formed with a handle (it and a flexible pawl If the handle is depressed the pawl will he brought into engagement with the ratchet teeth, and due to the flexibility of thepawl and thefrictional engagen' 'ent of member 28 with the hub of the ratchet wheel the member and ratchet will be shifted slightly relative to each other. i The action is illustrated more particularly inFig;6,"which"shows the handle 64: in (lee pressed position. As the handle is depressed, the member 63 is swung on its pivot, 'c'ausing the anchored endof the pawl 65 to move to thefleft. The flexibility-0 f the pawl per: nrits it to bend as its free end is held' bya ratchet tooth but the pawlfen'd ism'oved to the leftas the me'niber 63 tilts,causing rel-ative movement between the member 123 vwhich carries the pawl pivot and also plate 61, and the ratchet 21. This is desirableoccasionally in the operation of the machine'in order to compensate for the wear on the grinding wheel-carried by the tool head. v

- "It will be observedthat when handle 64 is depressed the cam 45 and the plate 61 are both shifted relative to the ratchetw-heel but preserve their-angular relation relative; to each other. The amount .of the slow feed preceding its termination byplate 61 is thus unaffected bv the adjustment for wear of the grinding wheel.

I claim: j

1. A grinding machine having feed mechanism including a ratchet, a pa'wl'carr'ier movably- -m0unted' adjacent "the ratehet; a pawl movably mounted on thepawl carrier and engageable with the teeth of the ratchet, means for-moving the .pawlcarrier periodically toc-causemovement of the paw-l and ratchet, and manually "operable mechanism having engagement both with the pawla'nd the pawl carrier. for. disengagingithe .pawl from the ratchet and moving the earirier out of the rangeof thesaid means.

1 "2. A- grinding machine having, feed'mechanism including a ratchetQapawlcarriermovably'mounted adjacent the ratchet, 'ajpawl movably mounted on the pawl carrier; and v engageable with the teeth of the ratchet, means for moving the. pawl carriervperiod-i callv to causesmove'mentof the pawland ratchet, anal.- 'mea'ns manually movable The a cam carried by saidmember, mechanism v operable by the cam to decrease the feeding movement of the pawl mechanism, a plate also carried by said member positioned to pass between the pawl and ratchet to prevent further feeding action, and means for adjusting the member relative to the ratchet.

4:. A grinding machine having feed mechanism including a ratchet, pawl mechanism operable to advance the ratchet step by step, means for decreasing the advancing motion of the pawl mechanism at a predetermined 7 period in the operation of the ratchet, meansfor disengaging the pawl from the ratchet at a predetermined period in the operation of the ratchet, and a device for adjusting said two means simultaneously with regard to the ratchet without varying their positions with respect to each other. a

5. A grinding machine having feed mechanism including a ratchet, a bearing member adjacent the ratchet, a pawl carrier pivoted to said member, a pawl pivoted to the pawl carrier, a pair ofslides reciprocable in said member one of which engages the pawl carrier and the other the pawl, means for imiparting reciprocating motion to the carrierengaging slide,-and a handle pivotedfto said member and engageable with pawl-engaging slide to move the pawl out of engagement with the ratchet; t

6. A grinding machine having feed mechanism including a ratchet, a bearing member adjacent the ratchet, a pawl carrier pivoted to said member, a pawl pivoted to the pawl carrier and-engageable with the ratchet, a

pair of slidesreciprocable in said member, one of which engages the pawl carrier and the other the pawl, a device havinga constant amplitude of motion engaging'said carrier-engaging slide, a rocker pivoted to said member and also .engageable with the carrier-engaging slide to limit its motion towards said device, a rocker actuating cam rotatable with the ratchet, a. handle pivoted to said member and engageable with the pawl-engaging-slide whereby the latter may be moved to disengage the pawl from the means for moving the pawl carrier periodi cally to cause movement of the pawl and ratchet, and a pawl lifter member mounted for movement towards and away from the pawl independently of the pawls own state of motion for imparting an impact blow against the pawl to disengage it from the ratchet.

nism including a ratchet, a pawl carrier movably mounted adjacent the ratchet, a pawl movably mounted on the pawl carrier and engageable with the teeth of the ratchet, a

pawl lifter mounted for movement towards and away from the pawl, automatically operating means for varying the amplitude of movement of the pawl carrier during the sequence of its operation, and means for moving the pawl lifter to cause displacement of thepawl from its contact with the ratchet by 8. A grinding machine having feed mechaan impact blow against the pawl imparted through movement of the pawl lifter.

In testimony whereof I have atfixed my signature.

CHARLES E. 'VAN NORMAN.

ratchet, and a connection between said pawl engaging slide, and handle pivoted to said latter willvbe actuatedindependently of the cam.

'Z. A grinding machine having feed mecha-' nism including a ratchet, a pawl carrier mov- CERTIFICATE OF CORRECTION.

Patent No. 1,788,475. Granted January 13, 1931, to

CHARLES E. VAN NORMAN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, line 58, claim 6, strike out the comma and words and a handle pivoted to said" and insert instead and the rocker whereby the; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 17th day of February, A. D. 1931.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

